An aircraft propulsion engine comprises auxiliary equipment which is mounted on its case and performs a certain number of functions connected with the ancillaries of the engine or of the aircraft. Thus, a multiple-flow turbojet engine is generally fitted with a thrust reverser formed, for example, of flaps or doors which bear against the fan case and the flap or door drive mechanism of which is housed in the annular space situated between the case and the cowl of the nacelle. This mechanism comprises a plurality of flap drive actuators, distributed around the case and oriented in the longitudinal direction.
Despite their peripheral positioning, adjacent to the exterior wall, the thrust reverser actuators are, in operation, subjected to temperatures which are liable to exceed those permitted by this equipment. This problem notably arises when taxiing when the airplane is being maneuvered on the ground. Specifically, whereas the equipment is sufficiently ventilated when the aircraft is in flight, on the ground the volume of air circulating around the equipment is not enough to perform this function.
The problem of cooling also affects the other equipment present in this annular space, such as on-board computers or processers of the EEC type, the function of which is notably to control the actuators of the engine to optimize the performance thereof.
It is known practice to ventilate this equipment by circulating cooling air around the affected equipment using a system of ducting placed on the case and supplied by an air circulation blower or even by bleeding air from the upstream part of the nacelle. Suitable diffusers are arranged in the zones that are to be ventilated. This then solves the problem of cooling the equipment when that is necessary.
However, these technical solutions add parts that have to be mounted within the engine environment. They make the engine heavier and complicated to assemble. Moreover, it should be noted that the empty space in the fan cowl zone is very confined and very cluttered. It would therefore seem desirable to reduce the volume of and to simplify the system that ventilates this equipment, namely the blower, the ducting, mounts and diffuser.
The applicant has set itself the objective of developing an improved ventilation system which combines the following properties: effective cooling, lightness of weight, low cost, compact volume.